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deep-space-netwerk · 8 months

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Alright, so, black holes right?

Most people have probably seen this astOUNDING image of the black hole at the center of the M87 galaxy - the first real picture of a black hole.

It may look like a blurry orange donut, but you gotta understand, this was and still is a hugely impressive achievement. At a black hole's event horizon, the escape velocity (or the speed at which something has to travel to escape the body's gravitational pull) is faster than the speed of light. By definition a black hole cannot be directly observed. Imaging the shadow of M87* required using eight ground-based radio telescopes all over the world, working together as an interferometer - or as though they were one single telescope the size of the entire planet.

So that's fucking cool in its own right, but how did we know that black holes existed before 2019 when we could actually "see" one? How do we detect something that reflects no light when we DON'T have a simulated telescope the size of Earth? The answer is gravity.

We think that most large galaxies have supermassive black holes at their centers, left over from their chaotic infancies when hundreds of thousands of early stars collided and then collapsed, and then kept colliding. To give you an idea of what we mean by "supermassive", the black hole at the center of the Milky Way, Sagittarius A* (pronounced "A-star"), is about 4 million times the mass of our sun. And that's SMALL.

So while black holes aren't the horrible all-consuming reality-guzzling unmakers of creation that science fiction likes to paint them as - we aren't in any danger whatsoever from Sagittarius A*, now or ever - they CAN get big enough to really throw things around. So we looked for objects moving under the influence of . . . nothing.

This gif is a years-long timelapse of stars orbiting something in a seemingly-empty region of space the center of the Milky Way, the approximate location marked with a red plus sign.

That something is Sag A*. It's an invisible behemoth, made of the extraordinarily dense remains of the birth of our galaxy, juggling entire solar systems the way Jupiter flings asteroids. And for so long, we couldn't even see it.

This shit makes me go fucking crazy. Imagine what else is out there that we don't understand just because we don't have the tools to even know it exists! Not just in space, in any field of scientific study!

It wasn't until the 1990s that we started realizing trees talk to each other, and now we know there's fungal mycelium networks that connect trees across entire continents. Just THIS YEAR we discovered an entirely new ecosystem underneath the hydrothermal vents in the deepest parts of the ocean floor. For most of human history, the existence of planets around other stars was highly debated, and now we've confirmed over 5 thousand of them. We even know what some of their atmospheres are made of!

There's a saying that "the more you know, the more you know you'll never know", and I feel like there's never been a time in history when that's been more true. And it's almost comforting, y'know? The universe is so vast, it feels correct that we shouldn't be able to understand all of its intricacies.

Reality is stranger than fiction, and the reality is there's stuff out there that we don't even have the words to begin to describe. Until we do! And our reward is even more questions!

#space #black holes #Sagittarius A*#M87 #Doesn't that gif just give you chills #Whole stars!#Orbiting N O T H I N G #Any time someone mentions black holes I have to pull up this gif and make sure everyone has seen it #My friends are very patient with me #Thanks @literallymechanical for the post suggestion!#spost #space post

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